DataTable is used to store data in memory in SQL database. DataTable contains a collection of constraints .in data base datatable is a collection of rows and columns. Datatable is ideal for this purpose, as you can take objects from memory and display the results in controls such as DataGridView in Windows Forms. Here are the simply c sharp example which shows DataTable
Below are the examples which shows about DataTable
//these lines are for creating a new connection by passing server name,uid,password and name of the database as here mind.
SqlConnection con = new SqlConnection("server=abc-pc1\\sqlexpress; uid=sa; password=sa; database=mind");
//create a data adapter and invoking the command.
SqlDataAdapter ad = new SqlDataAdapter("select * from Employee", con);
DataSet ds=new DataSet();
//Creating a Datatable object
DataTable dt = new DataTable();
dt = ds.Tables["Employee"];
// close the coonection